diff -r e24348a560a6 -r b72c6db6890b src/dbus/qdbuspendingreply.cpp
--- a/src/dbus/qdbuspendingreply.cpp	Fri Jun 11 14:24:45 2010 +0300
+++ b/src/dbus/qdbuspendingreply.cpp	Wed Jun 23 19:07:03 2010 +0300
@@ -252,7 +252,7 @@
 
 void QDBusPendingReplyData::assign(const QDBusMessage &message)
 {
-    d = new QDBusPendingCallPrivate; // drops the reference to the old one
+    d = new QDBusPendingCallPrivate(QDBusMessage(), 0); // drops the reference to the old one
     d->replyMessage = message;
 }
 
@@ -271,6 +271,7 @@
 void QDBusPendingReplyData::setMetaTypes(int count, const int *types)
 {
     Q_ASSERT(d);
+    QMutexLocker locker(&d->mutex);
     d->setMetaTypes(count, types);
     d->checkReceivedSignature();
 }